KR101835387B1 - Terminal and method for scheduling resources thereof - Google Patents

Terminal and method for scheduling resources thereof Download PDF

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KR101835387B1
KR101835387B1 KR1020110041044A KR20110041044A KR101835387B1 KR 101835387 B1 KR101835387 B1 KR 101835387B1 KR 1020110041044 A KR1020110041044 A KR 1020110041044A KR 20110041044 A KR20110041044 A KR 20110041044A KR 101835387 B1 KR101835387 B1 KR 101835387B1
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ack
spare
accumulation
threshold value
scheduling
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KR1020110041044A
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KR20120122715A (en
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정정수
김영용
안우진
박경민
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삼성전자주식회사
연세대학교 산학협력단
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00Arrangements for detecting or preventing errors in the information received
    • H04L1/12Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18Automatic repetition systems, e.g. van Duuren system ; ARQ protocols
    • H04L1/1829Arrangements specific to the receiver end
    • H04L1/1854Scheduling and prioritising arrangements

Abstract

The present invention relates to a terminal and a method for scheduling resources in the terminal, the method comprising the steps of: calculating a variation level according to a change in a segment transmission amount when a feedback transmission period for feeding back an ACK for a received segment comes; Determining whether the level of variation is greater than a scheduling threshold for accumulating and scheduling a spare ACK, and if the level of variation is greater than the scheduling threshold, performing ACK scheduling to transmit the spare ACK and to transmit the ACK . Therefore, it is possible to reduce the probability of spurious timeout of the TCP sender due to the variation of the wireless channel and the scheduling delay.

Description

TECHNICAL FIELD [0001] The present invention relates to a terminal and a resource scheduling method in the terminal,

The present invention relates to a terminal and a method for scheduling resources in the terminal, and more particularly, to a method for scheduling to transmit an Ack for data received from a base station in a terminal.

Transmission Control Protocol (TCP) has been developed to efficiently utilize limited bandwidth by controlling the transmission rate of the sender, and to prevent overloading of the network. TCP traces the Round Trip Time (RTT) according to the Packet Sequence Number (PSN) of the packet transmitted by the sender and the ACK received in response to the packet, thereby varying the packet transmission method. Therefore, when the network congestion is low, the sender increases the number of concurrent transmission packets by increasing the congestion window through techniques such as slow start and congestion avoidance. On the other hand, when packet loss occurs due to congestion of the network on the route, -out, and window halving to reduce the congestion window and reduce the transmission rate.

TCP is a technique developed based on a wired communication environment and unnecessary performance deterioration frequently occurs because it is used without being reflected in characteristics of a wireless communication environment. Generally, in a wired communication environment, a packet error or a packet loss due to a buffer overflow of a router is a main factor causing time-out or window halving do. However, when a wireless network is added to an end-user terminal, latency due to resource allocation may be larger than that of a wired environment as a plurality of terminals share limited resources. Also, when the channel condition deteriorates, a large amount of data can not be transmitted regardless of the resource distribution situation.

In this case, although packet loss does not actually occur, an unnecessary time-out (spurious time-out) occurs due to a delay spike caused by the wireless network. That is, although the RTT increases and the ACK actually arrives at the base station, the sender declares a time-out due to the packet loss, unnecessarily reducing the congestion window. As a basic function of TCP, it is possible to control a certain part, but the probability of spurious time-out is large when the mobility or channel fluctuation of the terminal is large.

Accordingly, in order to solve such a problem, the present invention proposes a method of scheduling resources in a terminal and a terminal, and transmitting the scheduled resources to a base station.

In order to solve the above problems, a resource scheduling method of the present invention includes the steps of calculating a fluctuation level according to a change in a segment transmission amount when a feedback transmission period for feeding back an ACK for a received segment comes, Determining whether the level is greater than a scheduling threshold for accumulating and scheduling spare ACKs; and performing ACK scheduling for transmitting the spare ACKs and transmitting the ACKs if the level is greater than the scheduling threshold value do.

In order to solve the above problems, the resource scheduling terminal of the present invention includes a variation level calculating unit for calculating a variation level according to a change in a segment transmission amount when a feedback transmission period for feeding back an ACK for a received segment comes, Determining whether the calculated variation level is greater than a scheduling threshold for accumulating and scheduling a spare ACK, and if the variation level is greater than the scheduling threshold, performing an ACK scheduling for transmitting the spare ACK and transmitting the ACK, And a scheduling unit.

The present invention can reduce the occurrence probability of spurious time-out of the TCP sender due to the variation of the wireless channel and the scheduling delay. To do this, the sender side obtains a large RTO value in order to withstand a relatively large RTT than the wired environment, and the ACK transmission interval is uniformly scheduled on the receiver side regardless of the actual data arrival interval arriving at the receiver. This process can solve the problem of delay spike or high RTT variance which is frequently seen in wireless environment.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram illustrating a method for transmitting an accumulated Ack according to an embodiment of the present invention.
2 is a diagram illustrating an Ack periodically transmitted in accordance with the present invention;
Figure 3 shows the amount of Ack accumulated according to the invention;
4 is a diagram illustrating a configuration of a terminal according to an embodiment of the present invention.
5 is a diagram illustrating an Ack scheduling method according to an embodiment of the present invention.
6 illustrates a method for calculating a variation level for determining scheduling in accordance with an embodiment of the present invention.
7 is a diagram illustrating a method of accumulating a spare Ack according to an embodiment of the present invention.
8 is a diagram illustrating a scheduling method according to a spare Ack accumulation amount according to an embodiment of the present invention.

Hereinafter, the operation principle of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

The delay injection technique inserts an artificial delay of a certain size when ACK is transmitted at specific time intervals. The retransmission timer (RTO) on the TCP sender side is determined by the sum of the smoothed average and the mean deviation of RTT (Round Trip Time) corresponding to the arriving ACKs. At this time, since the increment of RTO due to the average deviation value is large, the sender obtains a relatively large RTO value by generating an artificially small deviation. The delay injection technique is based on a fixed time-fixed delay (FTFD), a fixed time-random delay (FTRD), a random time-random delay (FTRD) .

The present invention is designed to transmit Ack according to the change of wireless environment in order to minimize unnecessary bandwidth waste by using delay injection. More specifically, the UE uses a channel fluctuation level, a Segment Arrival Rate (SAR), and an Ack Transfer Rate (ADR) The time and delay values can be determined. Also, in order to facilitate the implementation of the technology, all operations are handled in the terminal and the existing TCP technology is not changed.

In order to realize this, the constitution of the present invention can be largely divided into two. The first is the process of increasing the RTO of the TCP sender by gradually increasing the delay of the TCP receiver. In the above procedure, the ramping factor r is determined according to the channel variation level, and the delay is gradually increased according to the formula determined by r . When a delay is added to the ACK transmission, the sender side increases the RTO in response to the increased RTT. In this case, the possibility of time-out due to artificial delay insertion is minimized because a ramping-up type delay is added.

The second is the process of accumulating and consuming delayed ACKs by delay injection to uniformly adjust the ACK transmission interval of the TCP receiver. If the ACK transmission is delayed, an ACK which is in a transmission waiting state is accumulated in the buffer of the terminal. Therefore, if the SAR is sharply decreased due to channel fluctuation and channel quality deteriorates, the UE can maintain the RTT by transmitting an ACK at an interval similar to the previous time using the accumulated ACK (Spare ACK). In addition, even if the channel quality is rapidly improved and the SAR is increased, the terminal does not increase the ADR immediately but accumulates the spare ACK by maintaining the ADR at a level similar to the previous one in consideration of the channel fluctuation.

1 is a diagram illustrating a method of transmitting accumulated Acks according to an embodiment of the present invention.

Referring to FIG. 1, in a network in which CQI feedback (periodic CQI feedback) is performed at a period of T to feed back channel state information on a segment received between a BS and a UE, channel quality decreases , The interval of the ACK transmitted after 2T may increase more than twice when the segment transmitted is reduced to half of the previous half. That is, six ACKs 110a, 110b, 110c, 110d, 110e and 110f are transmitted in the T period and three ACKs 110g, 110h and 110i in the 2T period depending on the channel quality.

In this case, when the UE inserts a delay into the ACK transmission, 120f of the ACKs 120a, 120b, 120c, 120d, 120e, and 120f transmitted in the T period remain in the buffer of the UE. The remaining ACKs in the buffer can be used as spare ACKs. Therefore, even when the segment received after 2T decreases, the terminal can maintain the ACK transmission interval at a level similar to the previous period by using the spare ACK 120f accumulated at the T point. The processes of accumulating and transmitting spare ACKs operate in units of the CQI feedback period, and when the resource allocation according to the CQI feedback and the variance of the segment transmission amount become more than a specific value, the UE starts to operate.

The method of accumulating the spare ACK by delaying the ACK according to the channel state can be performed as follows.

The terminal maintains the segment transmission amount information (a) of k previous periods. Here, the segment transmission amount is defined as the number of TCP segments received in one period. (N-1) T, the rate of change of the segment transmission amount is calculated through Equation (1), assuming that the segment transmission amount of immediately preceding two periods is anT and a (n-1)

Figure 112011032199550-pat00001

The change rate calculated through Equation (1) is obtained in the form of a product in a change amount of the segment transmission amount in k previous periods, and a fluctuation level at the nT time is obtained through Equation (2).

Figure 112011032199550-pat00002

Where n is from 1 to

Figure 112011032199550-pat00003
. Then, the terminal determines whether the computed variation level A nT is greater than a scheduling threshold TH A for accumulating and scheduling a spare ACK. If the variation level is greater than the scheduling threshold, the terminal accumulates a spare ACK and performs ACK scheduling using the accumulated spare ACK. To do so, the terminal obtains a delay control value d by using Equation (3) based on the variation level A nT .

Figure 112011032199550-pat00004

At this time, d has a value between 0 and 1. When d is obtained and the new period starts, the terminal expects the SAR to decrease at a rate of d each time in the next period since the current point in time. That is, if the ADR of the last period at the nT time point is defined as ADR (nT), the terminal calculates the number of segments expected to arrive at the next two periods, respectively

Figure 112011032199550-pat00005
, Can be defined as dogs. And the terminal receives the
Figure 112011032199550-pat00006
= ≪ / RTI > an ACK transmission interval that increases in the form of a ramping up with respect to ACKs corresponding to N segments is calculated through Equation (4).

Figure 112011032199550-pat00007

The terminal can estimate the direction in which the number of segments received in the next two periods decreases, using the last period SAR and the variation level value. Then, the terminal performs delay injection using the delay value calculated by Equation (4). In other words, the MS calculates the ACK transmission interval using the delay value, and schedules the transmission time of each segment according to the calculated ACK transmission interval.

If a larger number of segments arrive than the predicted number of segments, the terminal adds delay to the segment arrival point and transmits an ACK as scheduled. When the delay is added, the UE can increase the occupancy rate of the spare ACK queue. On the other hand, if fewer segments arrive and ACK scheduling is not appropriate, the terminal sends an ACK as soon as the segment arrives.

Thereafter, according to the situation where the spare ACK is stored in the buffer, the terminal adjusts the accumulation amount of the spare ACK by changing the ACK scheduling method. At this time, the spare ACK accumulation amount may mean the number of ACKs remaining in the buffer or the ratio of the number of ACKs remaining in the buffer to the number of originally transmitted ACKs at the current time. Here, the spare ACK accumulation amount is assumed to be the ratio of the number of ACKs remaining in the buffer to the number of ACKs to be transmitted originally.

The accumulation minimum threshold TH q , where the spare ACK accumulation occupancy is set to the minimum amount at which the spare ACK can accumulate . low (For example, 0.2), the terminal can accumulate the spare ACK at each end of the cycle, increasing the ACK transmission interval based on the updated ADR and the variation level.

If the spare ACK occupancy is greater than the accumulation minimum threshold, the terminal performs the ADR control step. In the ADR control step, the terminal compares the SAR and the ADR of the previous cycle, analyzes the consumption and accumulation of the spare ACK, and controls the transmission interval of the next cycle according to the result.

The accumulation holding threshold value TH q, in which the spare ACK accumulation amount (queue occupancy) is set so that a certain amount of spare ACK can be maintained . middle, and an accumulation maximum threshold TH q, which is set to the maximum amount at which the spare ACK can be accumulated to the maximum . up , The mobile station can consider the situation that the amount of spare ACK accumulation is not excessively high or low. Therefore, it is the primary goal of the terminal to maintain the ADR as much as possible even if the SAR is suddenly changed. Accordingly, the UE transmits an ACK with the same ACK transmission interval (= 1 / ADR) according to the ADR of the previous cycle. If the SAR is larger than the ADR at the end of the cycle, since the number of arriving segments is greater than the number of transmitted ACKs, the spare ACK is accumulated. Conversely, if the SAR is smaller than the ADR, more ACKs are transmitted than the number of arriving segments. It can be seen that ACK is consumed.

On the other hand, if the spare ACK accumulation amount is larger than the accumulation maximum threshold value, the UE may set the ADR to be lower than necessary, or the channel quality may continuously increase and the spare ACK should be consumed. At this time, the accumulation maximum threshold value is preferably 0.8. Therefore, in this case, the terminal operates only in the direction of increasing the ADR.

If the SAR of the immediately preceding period is smaller than the ADR, since the spare ACK is consumed, the terminal transmits an ACK at the same interval (= 1 / ADR) as the previous cycle even in the next cycle. On the other hand, if the SAR is larger than the ADR, since the spare ACK is accumulated, the terminal sets the ACK transmission interval according to the SAR of the previous period (interval = 1 / SAR) to consume the spare ACK at a higher rate. The process of consuming the spare ACK is repeated until the spare ACK accumulation amount falls below the accumulation holding threshold value. At this time, the accumulation holding threshold value is preferably 0.5.

Spare ACK accumulation amount accumulation minimum threshold TH q . If less than the low, in other words Channel quality is continuously reduced as an ACK is less available spare terminal, re-increase the ACK transmission interval and stores the spare ACK.

Through these procedures, the UE can adjust the ACK transmission interval according to the amount of spare ACKs accumulated. That is, the terminal can adjust the transmission interval of ACK according to SAR and ADR as shown in FIG. It is noted that the accumulation minimum threshold, accumulation holding threshold, accumulation maximum threshold may be set differently according to the communication environment and the experimental environment of the terminal.

2 is a diagram illustrating an Ack periodically transmitted according to the present invention.

Referring to FIG. 2, during the (T, 5T) period in which the operation starts, the ADR is continuously lowered by inserting an artificial delay into the ACK transmission in the delay injection step. If the spare ACK accumulation amount exceeds the accumulation minimum threshold value, the process proceeds to the ADR control step of controlling the ACK transmission interval. Therefore, in the (5T, 9T) interval, the ADR is fixed to the (4T, 5T) period, and the ACK is transmitted at the same interval irrespective of the SAR while consuming or accumulating the spare ACK.

3 is a diagram showing the amount of Ack accumulated according to the present invention.

Referring to FIG. 3, the amount of spare ACK accumulation at the 4T time point is equal to or greater than the accumulation maximum threshold value, and the process proceeds to the spare ACK decreasing step. (4T, 5T), the terminal sets the ACK transmission interval based on the SAR instead of the ADR of the previous period (interval = 1 / (SAR (3T, 4T) ))). Similarly, since the SAR of the (5T, 6T) interval at 6T is higher than the ADR, the terminal increases the ADR based on the previous SAR. After the ADR is sufficiently consumed at the time of 7T, if the accumulation amount becomes less than 50% of the accumulation holding threshold value, the terminal performs a fixed ADR step of controlling the ACK transmission interval according to the ADR of the previous period, do. Also, if the spare ACK accumulation amount is less than the accumulation minimum threshold value at the time of 8T, the UE calculates a scheduling control value and a transmission interval according to the accumulated ACK accumulation amount, and proceeds to a delay injection step of controlling an ACK transmission interval. As shown in FIG.

In the above description, the process of adjusting the spare ACK accumulated through the SAR and ADR and scheduling and transmitting the ACK is explained. These processes will now be described in detail with reference to FIGS. 4 to 8. FIG.

4 is a diagram illustrating a configuration of a terminal according to an embodiment of the present invention.

4, a terminal includes a segment transmission amount change calculation unit 415, a variation level calculation unit 420, an ACK scheduling unit 425, and an ACK scheduling unit 420 included in the control unit 410 and the control unit 410 and for performing ACK scheduling, An ACK storage unit 430, and a communication unit 440.

The controller 410 controls the states and operations of all the constituent elements of the terminal. Here, the control unit 410 may schedule the ACK according to the channel state in the network periodically performing the COI feedback. More specifically, when the CQI feedback is transmitted at a specific period, the control unit 410 may check the rate of change of the segment transmission rate of the previous period and insert a delay when transmitting the ACK. At this time, the controller 410 stores the ACK not transmitted in the current period in the ACK accumulator 430, which is a buffer. The controller 410 uses the ACK stored in the ACK accumulator 430 as a spare ACK. Next, the control unit 410 can schedule the ACK according to the accumulated spare ACK amount. In order to perform these processes, the control unit 410 includes a segment transmission amount change calculation unit 415, a variation level calculation unit 420, and an ACK scheduling unit 425.

The segment transmission amount change calculation unit 415 calculates the segment transmission amount change amount by the number of TCP segments received in one period. More specifically, the segment transmission amount change calculation unit 415 calculates the change rate as the segment transmission amount immediately before two cycles based on the current cycle.

The fluctuation level calculating unit 420 calculates the fluctuation level of the current point by calculating the change amount of the segment transmission amount in the product form in k periods before the rate of change calculated through the segment transmission amount change calculating unit 415. [ The variation level calculation unit 420 determines whether the calculated variation level is equal to or greater than a scheduling threshold value for accumulating and scheduling a spare ACK.

The ACK scheduling unit 425 calculates a delay control value d based on the variation level when the calculated variation level is equal to or greater than the scheduling threshold value. Then, the ACK scheduling unit 425 predicts that, at the beginning of a new period, the SAR decreases at a rate of d each time. Next, the ACK scheduling unit 425 calculates an ACK transmission interval that increases in a ramping up manner with respect to ACKs corresponding to segments received in the next period. The ACK scheduling unit 425 schedules the transmission time of each segment according to the calculated ACK transmission interval.

In addition, the ACK scheduling unit 425 schedules the ACK according to the situation where the spare ACK is stored in the buffer, thereby adjusting the amount of spare ACK. For example, if the spare ACK accumulation amount is smaller than the accumulation minimum threshold value, the ACK scheduling unit 425 can schedule an ACK at each end of each cycle, increasing the ACK transmission interval based on the updated ADR and the variation level. In this case, the controller 410 controls the ACK accumulator 430 to accumulate ACKs not transmitted in the current period as spare ACKs.

If the spare ACK accumulation amount is larger than the accumulation minimum threshold value, the ACK scheduling unit 425 performs the ADR control step. In the ADR control step, the ACK scheduling unit 425 compares the SAR and ADR of the immediately preceding period to analyze the consumption and accumulation level of the spare ACK, and controls the ACK transmission interval of the next cycle according to the result.

If the spare ACK accumulation amount is greater than or equal to the accumulation holding threshold value and less than the accumulation maximum threshold value, the ACK scheduling unit 425 schedules the ACK so as to maintain the ADR as much as possible. Therefore, the ACK scheduling unit 425 schedules the ACK with the same ACK transmission interval by fixing the ADR of the previous cycle.

On the other hand, if the spare ACK accumulation amount is larger than the accumulation maximum threshold value, the ACK scheduling unit 425 confirms the SAR of the previous cycle. If the SAR of the previous cycle is smaller than the ADR, since the spare ACK is consumed, the ACK scheduler 425 schedules the ACK at the same interval (= 1 / ADR) as the previous cycle even in the next cycle. On the other hand, when the SAR is larger than the ADR, since the spare ACK is accumulated, the ACK scheduling unit 425 schedules the ACK transmission interval based on the SAR of the previous period to consume the spare ACK at a higher rate.

Spare ACK accumulation amount accumulation minimum threshold TH q . the ACK scheduler 425 increases the ACK transmission interval again and accumulates the spare ACKs when the channel quality is continuously decreased and the available spare ACKs are small.

The control unit 410 controls the communication unit 440 to transmit the scheduled ACK from the ACK scheduling unit 425. At this time, the controller 410 controls the ACK accumulator 430 to store an ACK not transmitted in the current period as a spare ACK according to the scheduling.

The ACK accumulator 430 performs a function of storing a spare ACK that can be transmitted in the next transmission period without being transmitted in the current transmission period according to the ACK scheduling. Here, the ACK accumulation unit 430 may be a buffer.

The communication unit 440 transmits and receives data to / from an external terminal. Here, the communication unit 440 may transmit the scheduled ACK according to the received segment under the control of the control unit 410. [ In other words, under the control of the controller 410, the communication unit 440 may transmit an ACK at an ACK transmission interval scheduled according to the variation level calculated according to the channel status.

5 is a diagram illustrating an Ack scheduling method according to an embodiment of the present invention.

Referring to FIG. 5, if a first feedback transmission period for feeding back an ACK for a segment received in step 510 is reached, the terminal calculates a variation level according to a change in the segment transmission amount in step 520. FIG. The process of calculating the variation level will be described later with reference to FIG.

The terminal determines in step 530 whether the change level is equal to or greater than the scheduling threshold value. If the variation level is greater than or equal to the scheduling threshold, the terminal accumulates the spare ACK in step 540 and may transmit the scheduled ACK according to the accumulation amount of the accumulated spare ACK. Here, the process of accumulating the spare ACK and transmitting the scheduled ACK will be described later with reference to FIG. 7 to FIG. Although not shown in the figure, if the variation level of the terminal falls below the scheduling threshold value, the base station informs that the spare ACK accumulation due to delay injection is to be ended.

6 is a diagram illustrating a method of calculating a variation level for determining scheduling according to an embodiment of the present invention.

Referring to FIG. 6, in step 610, the terminal checks the segment transmission amount information a of the previous period. In step 620, the terminal calculates a segment transmission amount change rate based on the segment transmission amount information. Finally, the terminal calculates the variation level of the current point of view by using the rate of change of the segment transmission amount calculated in step 630.

The terminal compares the calculated variation level with a scheduling threshold to accumulate a spare ACK, and may schedule and transmit an ACK accordingly.

7 is a diagram illustrating a method of storing a spare ACK according to an embodiment of the present invention.

Referring to FIG. 7, if the variation level is greater than the scheduling threshold, the terminal calculates the scheduling control value d in step 710. In step 720, the terminal calculates an ACK transmission interval based on the scheduling control value. The UE transmits an ACK according to the ACK transmission interval calculated in step 730, and accumulates the spare ACKs remaining in ACKs to be transmitted in the current period according to the transmission interval in the buffer.

In step 740, the terminal determines whether a second feedback transmission period, which is the next feedback transmission period, has arrived. If a second feedback transmission period arrives, the terminal calculates a variation level according to a change in the segment transmission amount in step 750. Since the process of calculating the variation level has been described with reference to FIG. 6, detailed description thereof will be omitted. In step 760, the terminal determines whether the variation level is greater than the scheduling threshold value.

If the variation level is greater than the scheduling threshold, the terminal checks the accumulated amount of spare ACK in step 770. In step 780, the MS schedules an ACK according to the amount of spare ACKs. Here, a process of scheduling ACK according to the amount of spare ACK will be described with reference to FIG. Finally, the mobile station transmits the scheduled ACK in step 790.

The UE can schedule and transmit an ACK in the next feedback transmission period according to the accumulation amount of the spare ACK. This process will be described later with reference to FIG.

8 is a diagram illustrating a scheduling method according to a spare Ack accumulation amount according to an embodiment of the present invention.

Referring to FIG. 8, in step 810, the terminal determines whether the accumulated amount of spare ACK is greater than a predetermined accumulated maximum threshold value. If the accumulated amount of the spare ACK is smaller than the predetermined accumulated maximum threshold value, the terminal determines in step 815 whether the accumulated amount of the spare ACK is greater than a predetermined accumulated minimum threshold value.

If the accumulation amount of the spare ACK is less than the predetermined accumulated minimum threshold value, the terminal calculates the scheduling control value d and the transmission interval again in step 820. The UE schedules the ACK according to the transmission interval calculated in step 825, and transmits the ACK according to the scheduling. Accordingly, the terminal can accumulate a spare ACK. If the accumulation amount of the spare ACK is greater than the accumulation minimum threshold value in step 815, the UE schedules the ACK according to the rate at which the ACK was transmitted in the immediately preceding feedback transmission period in step 830, and transmits the ACK according to the scheduling . At this time, the MS schedules ACK at an interval of 1 / ADR. Through this process, the terminal can keep the current amount of the spare ACK constant.

If the spare ACK accumulation amount is greater than the accumulated maximum threshold value in step 810, the terminal checks the SAR in the immediately preceding feedback transmission period immediately before step 840. The terminal determines whether the 1 / SAR determined in step 845 is larger than 1 / ADR. If 1 / SAR is greater than 1 / ADR, the terminal schedules an ACK at a 1 / SDR interval in step 850 and transmits an ACK according to the scheduling. On the other hand, if 1 / SAR is smaller than 1 / ADR, the terminal schedules an ACK at a 1 / ADR interval in step 855 and transmits an ACK according to the scheduling.

When the third feedback transmission period arrives, the terminal calculates the variation level in the third feedback transmission period in step 860. [ That is, the MS confirms the segment transmission amount information of the second feedback transmission period and calculates the segment transmission amount change rate based on the confirmed segment transmission amount information. Finally, the terminal calculates the variation level of the current third feedback transmission time point using the calculated segment transmission rate change rate. Then, the terminal determines whether the variation level calculated in step 865 is larger than the scheduling threshold value. If the variation level is greater than the scheduling threshold, the terminal determines in step 870 whether the amount of spare ACK accumulation currently stored is greater than the accumulation retention threshold.

If the amount of spare ACK is greater than the accumulation holding threshold, the terminal returns to step 840 and performs the processes of consuming the stored spare ACK. On the other hand, if the spare ACK quantity is smaller than the accumulation holding threshold value, the terminal performs the process of maintaining or accumulating the spare ACK quantity in step 815.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the scope of the appended claims, and equivalents thereof.

Claims (14)

1. A resource scheduling method of a terminal,
Receiving at least one segment from a base station;
Calculating a variation level based on a change in the total amount of segments received during the previous feedback transmission period and the total amount of segments received during the feedback transmission period when a feedback transmission period for feeding back the ACK for the at least one received segment comes And,
Determining a delay value based on the variation level,
And transmitting an ACK for the received segment based on the determined delay value if the variation level is greater than a preset scheduling threshold.
The method of claim 1, wherein the step of transmitting the ACK comprises:
Calculating an ACK transmission interval for ACKs corresponding to a segment received in a next feedback transmission period based on the determined delay value;
And transmitting the ACK based on the calculated ACK transmission interval and accumulating a spare ACK remaining on the basis of the transmission interval.
3. The method of claim 2,
Confirming the accumulated amount of the spare ACK when the next feedback transmission period arrives;
And transmitting the ACK based on the spare ACK accumulation amount.
4. The method of claim 3, wherein the step of transmitting the ACK comprises:
Determining whether the spare ACK accumulation amount is larger than an accumulated maximum threshold value that is set to a maximum accumulation amount of the spare ACK;
Determining whether the spare ACK accumulation amount is larger than a storage minimum threshold value that is set as a minimum accumulation amount of the spare ACK if the spare ACK accumulation amount is smaller than the accumulation maximum threshold value;
Calculating the delay value and the transmission interval if the spare ACK accumulation amount is smaller than the accumulation minimum threshold value;
And transmitting an ACK based on the calculated transmission interval and accumulating the remaining spare ACKs.
5. The method of claim 4,
And transmitting an ACK based on an ACK transmission rate in a previous feedback transmission period if the spare ACK accumulation amount is larger than the accumulation minimum threshold value.
5. The method of claim 4,
Confirming a segment reception rate in a immediately preceding feedback transmission period if the spare ACK accumulation amount is larger than the accumulation maximum threshold value;
Comparing the received segment reception rate with an ACK transmission rate in a immediately preceding feedback transmission period;
And transmitting the ACK based on the comparison result.
The method according to claim 6,
Calculating a variation level of the feedback transmission period when the scheduling ACK is transmitted and the next feedback transmission period arrives;
Comparing the calculated variation level with a scheduling threshold value;
Determining whether the spare ACK accumulation amount is larger than the accumulation holding threshold value if the variation level is greater than the scheduling threshold value;
And accumulating the spare ACK based on a result of size determination of the spare ACK accumulation amount and the accumulation holding threshold value.
A communication unit for receiving at least one segment from the base station;
Calculating a variation level based on a change in the total amount of segments received during the previous feedback transmission period and the total amount of segments received during the feedback transmission period when a feedback transmission period for feeding back the ACK for the at least one received segment comes Determining a delay value based on the variation level, and transmitting an ACK for the received segment based on the determined delay value if the variation level is greater than a predetermined scheduling threshold value. Resource scheduling terminal.
9. The apparatus of claim 8, wherein the control unit
Calculating an ACK transmission interval for ACKs corresponding to a segment received in the next feedback transmission period based on the determined delay value, transmitting the ACK based on the calculated ACK transmission interval, And accumulates spare ACKs remaining in the resource scheduling terminal.
10. The apparatus of claim 9, wherein the control unit
And transmits the ACK based on the determined amount of spare ACK accumulation when the next feedback transmission period comes, checking the amount of spare ACK accumulated in the controller.
11. The apparatus of claim 10, wherein the control unit
If the spare ACK accumulation amount is larger than the accumulation maximum threshold value that is set so as to maximize the spare ACK, and if the spare ACK accumulation amount is smaller than the accumulation maximum threshold value, Determining whether the spare ACK is larger than the accumulated minimum threshold value set as the minimum accumulation amount, calculating the delay value and the transmission interval if the spare ACK accumulation amount is smaller than the accumulated minimum threshold value, And transmits the ACK based on the interval and accumulates the spare ACK.
12. The apparatus of claim 11, wherein the control unit
And transmits the ACK based on the ACK transmission rate in the immediately preceding feedback transmission period if the spare ACK accumulation amount is larger than the accumulation minimum threshold value.
12. The apparatus of claim 11, wherein the control unit
If the spare ACK accumulation amount is larger than the accumulation maximum threshold value, the segment reception speed is checked in the immediately preceding feedback transmission period, the ACK transmission speed in the immediately preceding feedback transmission period is compared with the segment reception speed, And transmits the ACK based on the ACK.
14. The apparatus of claim 13, wherein the control unit
Calculating a variation level of the feedback transmission period, comparing the variation level with a scheduling threshold, and if the variation level is greater than a scheduling threshold, And accumulates the spare ACK based on a result of determining the size of the spare ACK accumulation amount and the accumulation holding threshold value by determining whether the ACK accumulation amount is larger than the accumulation holding threshold value.




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